Calcaneus Bone Anatomy, Definition & Function | Body Maps Your message has been sent. OK We're sorry, an error occurred. We are unable to collect your feedback at this time. However, your feedback is important to us. Please try again later. Close Calcaneus Located within the foot, the calcaneus is also known as the heel bone. It is situated in the back of the foot, just below the talus, tibia, and fibula bones of the lower leg. Of all of the bones in the foot, the heel bone is the largest. The calcaneus has a unique design and structure. At the front, the heel bone features many curves to accommodate the talus and the many different tarsal bones, which lead to the metatarsals and phalanges that make up the front of the foot and toes. The back of the heel bone is not as complex, featuring a tuberosity and a medial process — landmark areas of the bone where muscles attach. The calcaneus provides insertion points for the abductor hallucis and the abductor digiti minimi muscles. At the back of the heel, the Achilles tendon inserts into the rough area located on the superior (upper) side.

This fibrous connective tissue, as well as other ligaments and muscles, is necessary for standing, walking, and running. As such, a broken or fractured calcaneus will make these movements difficult. Bones and Joints of the Foot and Ankle -footEducation Bones and Joints of the Foot and Ankle Overview Regions of the foot: Hind-foot – as the name suggests, the hindfoot is the portion of the foot closest to the center of the body. It begins at the ankle joint and stops at the calcaneal-cuboid joint. Mid-foot – The midfoot begins with the calcaneal-cuboid joint, and essentially ends where the metatarsals begin. While it has several more joints than the hind-foot, it still possesses little mobility. Fore-foot – the fore-foot is composed of the metatarsals and phalanges. The bones that comprise the fore-foot are those that are last to leave the ground during walking. Mobile Joints of the foot and ankle: Ankle joint Joints of midfoot or “Lisfranc” Joint (a.k.a.

tarso-metatarsal (TMT) joints or cuneiform-metatarsal joints) Bones of the lower leg and hind-foot: Tibia, Fibula, Talus, Calcaneous. Tibia and Fibula (Long Bones) Though the tibia (commonly called the shin bone) is not a part of the foot, it plays an important role. The foot is connected to the body where the bones of the foot and ankle meet the tibia and fibula (the small bone to the outside of the tibia). The tibia is also responsible for holding up 85% of the weight that presses down on the foot in the standing position. The tibia and fibula are held together by a tough layer of connective tissue, known as the Interosseous Membrane. The membrane thickens at the lower part of the leg, in order to make the ankle more stable. These two bones connect with the talus by forming a sort of dish which the talus fits into. This dish is known as the mortise of the ankle joint.

Talus The talus is something of an odd bone because of its strange shape and the fact that 70% of this bone is covered with hyaline cartilage (joint cartilage). The talus acts as a “ball joint”, playing the critical roll of connecting the lower leg to the foot. The talus is covered by so much cartilage because it connects so many different bones. The talus holds the ankle together by connecting to the lower leg with a ball joint, connecting to the calcaneous on the underside through the subtalar joint, and by helping connect the back part of the foot (hindfoot) to the midfoot via the talo-navicular joint. These series of connections allow the foot to rotate smoothly around the talus, as when you roll your ankle in a circle. Unfortunately, the talus has relatively poor blood supply, which means that injuries to this bone take greater time to heal than might be the case with other bones. Parts of the Talus The talus is generally thought of as having three or four parts: The talar body including the “dome” of the talus The talar neck The talar head The talar body is roughly square in shape and is topped by the dome.

It connects the talus to the lower leg at the ankle joint. The talar head interacts with the navicular bone to form the talo-navicular joint. The talar neck is located between the body and head of the talus, and is remarkable because it is one of the few areas of the talus not covered with cartilage, and is one of the few places that blood can flow to in the talus. Calcaneus (The Heel Bone) The calcaneus is commonly referred to as the heel bone. The calcaneus is the largest bone in the foot, and along with the talus, it makes up the area of the foot known as the hind-foot. The calcaneus is something like an oddly shaped egg; hard cortical bone on the outside covers softer cancellous bone on the inside. There are three protrusions on the top surface of the calcaneus (the posterior, middle, and anterior “facets”) that allow the talus to sit on top of the calcaneus, forming the sub-talar joint. The calcaneus also joins to another bone at the furthest end, away from the lower leg and toward the toes.

At this end, the calcaneus connects to the cuboid bone to form the calcaneal-cuboid joint. Subtalar Joint The talus rests above the calcaneous to form the subtalar joint. However, the talus does not sit directly on top of the calcaneus. Instead, it rests slightly offset toward the outside of the foot (the side nearest the little toe). This positioning allows the foot to cope with uneven terrain because it allows a little more flexibility from side to side. The subtalar joint doesn’t move independently; it moves along with the talo-navicular joint and the calcaneo-cuboid joint, two joints located near the front of the talus. Bones of the Mid-foot: Cuboid, Navicular, Cuneiform (3) Cuboid The cuboid bone is the main bone of the mid-foot. It is a square-shaped bone on the outside of the foot, and possesses several places to connect with other bones. The main joint formed with the cuboid is the calcaneo-cuboid joint. Farther along its length, the cuboid also connects with the base of the fourth and fifth metatarsals (the metatarsals of the last two toes).

On the inner side, it also connects with one of the lateral cuneiform bones. Calcaneo-cuboid Joint The calcaneal-cuboid joint attaches the heel bone to the cuboid. Navicular The navicular is located in front of the talus and connects with it through the talo-navicular joint. The navicular is curved on the surface nearest the ankle. The side farthest from the ankle joint connects to each of the three cuneiform bones. Like the talus, the navicular has a poor blood supply. On the inner side (closest to the middle of the foot), there is a piece of bone that juts out, which is called the navicular tuberosity. This is the site where the posterior tibial tendon anchors into the bone. Talonavicular Joint As the name suggests, the talo-navicular joint connects the talus to the navicular. The curve of the navicular is designed to connect smoothly with the front surface of the talus. This joint allows for the potential to have significant motion between the hindfoot and the midfoot, depending on the position the hindfoot is in.

Cuneiforms There are three different cuneiform bones present side-by-side in the midfoot. The one located on the inside of the midfoot is called the medial cuneiform. The middle cuneiform is located centrally in the midfoot, and to the outside is the lateral cuneiform. All three cuneiforms line up in a row and articulate with the navicular, forming the naviculo-cuneiform joint. The structure of the cuneiforms is similar to a roman arch. Each cuneiform connects to the others in order to form a more stable unit. These bones, along with the strong plantar and dorsal ligaments that connect to them, provide a good deal of stability for the midfoot. Bones of the Fore-foot: Metatarsals (5), Phalanges (14), Sesmoid Bones (2) Metatarsals Each foot contains five metatarsals. These are the long bones that lead to the base of each toe. The metatarsals are numbered 1-5, starting on the inside and leading outward (from big toe to smallest).

Each metatarsal is a long bone that joins with the mid-foot at its base, a joint called the tarsal-metatarsal joint, or Lisfranc joint. In general, the first three metatarsals are more rigidly held in place than the last two, although in some individuals there is increased motion associated with the 1st metatarsal where it joins the midfoot (at the 1st tarso-metatarsal joint), and this increased motion may predispose them to develop a bunion. The long part of the metatarsal bone is known as the metatarsal “shaft”, and the thick end of the bone nearest the toes is known as the metatarsal “head” (the metatarsal neck lies between the shaft and head). The head serves two very important functions: First, the metatarsal heads are the locations where weightbearing takes place. Second, the phalanges connect to the foot at the metatarsal heads at a joint called the metatarsal-phalangeal joint. These joints are very flexible, allowing the metatarsal heads to continuously support the weight of the body, as the foot moves from heel to toe.

First Metatarsal – The largest of the metatarsal, both in terms of length and width. Second Metatarsal – The fore-foot is made extremely stable not only by the ligaments connecting the bones, but also because the second metatarsal is recessed into the medial cuneiform, in comparison to the others. The second metatarsal may be overly long in some individuals, predisposing them to 2nd metatarsalgia . Fourth and Fifth Metatarsal – The fourth and fifth metatarsal may have greater range of motion than the others do. Phalanges The phalanges make up the bones of the toes. They are connected to the rest of the foot by the metatarsal-phalangeal joint. The first toe, also known as the great toe due to its relatively large size, is the only one to be comprised of only two phalanges. These are known as the proximal phalanx (closest to the ankle) and the distal phalanx (farthest from the ankle). The four “lesser toes” (toes 2-5) all have three phalanges.

The phalanx closest to the ankle is known as the proximal phalanx, which articulates with the “middle” phalanx, the proximal interphalangeal joint (PIP joint). The middle phalanx meets the “distal” phalanx at the distal interphalangeal joint. An imbalance in the tendons pulling across these small joints of the toes will lead to deformity of the toe, such as a clawtoe. A list of the joints of the toes can be found below. Inter-Phalangeal Joint (great toe only) Proximal Inter-Phalangeal Joint (PIP joint – toes 2-5) Distal Inter-Phalangeal Joint (DIP joint -toes 2-5) Sesamoid Bones A sesamoid bone is a bone that is also part of a tendon. An easy example of such a bone is the kneecap (patella). In the foot, there are two sesamoid bones, each of which is located directly underneath the first metatarsal head. These seasmoids are part of the flexor hallucis brevis tendon.

Edited October 17, 2015 Calcaneus | Heel Bone Calcaneus | Heel Bone Calcaneus or heel bone is the largest of tarsal bones. It projects posteriorly to form the prominence of heel, thus acting as a short lever for muscles of the calf. Left Calcaneus (Superior Aspect) Left Calcaneus (Medial Aspect) Structure of calcaneus: Calcaneus is irregularly cuboidal in shape. It consists of five different surfaces: Superior, Anterior, Posterior, Plantar and Lateral. Superior surface: Its superior surface is divisible into three parts. The most posterior 1/3 is rough and concavo-convex. The middle 1/3 carries the posterior talar facet. The anterior 1/3 is partly articular. Anterior to the articular region, there is a rough depression leading to a groove, the sulcus calcanei, on the medial side. The sulcus calcanei completes the sinus tarsi with talus. Anterior surface: The anterior surface is the smallest of all, and is actually an obliquely set concavo-convex articular facet for the cuboid bone.

Posterior surface: It is divided into three regions: Proximal, Middle and Distal. The middle region is the largest and is limited above by a groove and below by a rough ridge for calcaneal tendon. The distal region is the subcutaneous weight-bearing surface. Plantar surface: It is rought and forms the calcaneal tuberosity proximally. There are two laterally extending processes, separated by a notch. Lateral surface: It is almost flat and palpable on the lateral aspect of heel. Distally, it presents the peroneal tubercle. There is a deep groove for tendon of peroneus longus and a shallow groove for tendon of peroneus brevis on the lateral surface. Medial surface: This surface is vertically concave. The sustantaculum tali projects distally from the distal part of its upper border.Superiorly, the process bears the middle talar facets and inferiorly a groove continuous with that on the talar posterior surface for the tendon of flexor hallucis longus. Blood supply of calcaneus: Blood supply of calcaneus is derived from medial and lateral calcaneal arteries.

The medial calcaneal artery arises from posterior tibial artery while the lateral calcaneal artery arises from peroneal artery. There is also some degree of blood supply coming from peroneal artery, posterior calcaneal anastomosis, medial and lateral plantar arteries. Nerve supply to calcaneus: The calcaneus receives its nerve supply by branches of the tibial, sural and the deep peroneal nerves. Ossification of calcaneus: Calcaneus is the only tarsal bone, which has two centers of ossification. The main center appears prenatally in the third month. The second center appears in the sixth year and fuses in fourteenth year. This center covers most of posterior surface and a part of plantar surface. Share this page: Understanding The Anatomy of the Bones of the Foot Understanding The Anatomy of the Bones of the Foot Authored by Hindfoot & Tarsal Bones Over 25 percent of our bones are located in our feet. There are twenty-six bones that make up the complex structure of each foot. The foot is a strong mechanism, and it supports our entire body weight during all upright activities (standing, walking, running, etc).

It remains flexible, durable, and resilient under enormous pressure. Structurally, the foot consists of three main parts: the forefoot, midfoot, and hindfoot. Anatomically, the bones of the foot are known as the tarsal bones, metatarsal bones, and phalanges. Let’s break down each category and discuss the importance of each bone. Forefoot: Phalanges and Metatarsal Bones The forefoot comprises fourteen phalanges and five metatarsal bones. One phalanx of each of the five toes connects to one of the five metatarsals. The toes are numbered one through five, starting with the big toe, which is technically known as the hallux. Some people like to call the fifth toe the “pinky.” The phalanges are referred to as follows: The proximal phalanx is the base of each toe and articulates the metatarsal bone and middle phalanx. The middle phalanx is located under the distal phalanx in the second, third, fourth and fifth toes only. The hallux does not have a middle phalanx. The distal phalanx is found at the end of each toe, forming the tip of the toes.

There are five metatarsals in each foot. The metatarsals are the long bones located between the tarsal bones and the phalanges. Each metatarsal has a long shaft with two expanded ends called the base and the head. They form part of the foot’s arch and serve both as a major shock absorber and a weight-transfer mechanism. They are connected to the forefoot and midfoot by muscles, tendons, and a special ligament known as the plantar fascia. The metatarsals are not named individually; rather, they are numbered first through fifth, starting with the big toe. Here is a quick description of each of the metatarsal bones: The first metatarsal bone is the shortest and thickest. The second metatarsal bone is the longest and is firmly held between the first and third cuneiform bones. This bone is most susceptible to injury. The third metatarsal bone is in the middle and articulates the third cuneiform, as well as the second and fourth metatarsal bones. The fourth metatarsal bone is smaller than the third, but like the third it also articulates the surrounding metatarsals (the third and fifth), and also articulates the cuboid.

The fifth metatarsal bone articulates the cuboid and the fourth metatarsal. Jones fractures and stress fractures are common injuries to this bone. There are also two tiny bones located under the hallux (big toe) called sesamoid bones. Sesamoid bones develop within the tendon of a muscle to protect the tendon from wear and tear at the point where it passes over the end of the metatarsal bone. They bear the weight of the body when the toe pushes off in walking or running. Though it is less common, sesamoid bones can be found elsewhere in the foot within other flexor tendons of the toes. Midfoot: Lesser Tarsal Bones The five bones that make up the midfoot are collectively known as the lesser tarsal bones. They act as an intermediary to transfer weight from the hindfoot to the forefoot with each footstep. These bones, along with the joints and ligaments that connect them, make up most of what we would consider the arch of the foot. They include: The navicular bone is boat-shaped and located in the middle of the foot. It articulates with the talus and the three cuneiform bones.

The cuboid bone is shaped like a cube and is the last of the seven tarsal bones, articulating with the fourth and fifth metatarsal bones, calcaneus, and navicular bones. There are three cuneiform bones in all: medial, intermediate, and lateral. They are located in the midfoot region, articulating with the corresponding metatarsal bones and navicular bone. Hindfoot: Greater Tarsal bones The hindfoot connects the foot to the leg at the ankle joint, and comprises two large bones called the talus and calcaneus. These bones articulate with each other through the subtalar joint, and also link the hindfoot to the midfoot through the mid-tarsal joint. Here is a brief description of each of the tarsal bones: The talus connects the hindfoot to the two leg bones (the tibia and fibula) to form the ankle joint, which acts as a hinge to allow the foot to move up and down. It also links the hindfoot to the midfoot through the navicular bone to form one part of the mid-tarsal joint.

From below, the talus meets up with the calcaneus to form the subtalar joint, which allows the foot to move from side to side. The calcaneus is also known as the heel bone, and it is the largest bone in the foot. It connects with the talus from above to form the subtalar joint. It also meets up with the cuboid bone to form the rest of the midtarsal joint. This joint allows some motion between the hindfoot and midfoot that gives the foot some flexibility Medical References: H.F. Fullmann "Atlas of Anatomy" (Tandem Verlag GmbH, 2009) 100-101 Professor P. Abrahams "A Complete Guide to How the Body Works, The Atlas of the Human Body" (Amber Books, 2009) 222-224 Taber's Cyclopedic Medical Dictionary, 21 edition (F.A.

Davis Company, 2005) 893 This page was last updated on October 2nd, 2015 How To Maintain & Improve Your Foot Health A Complete Guide To The Anatomy Of The Foot Foot Bone Anatomy: Overview, Tarsal Bones - Gross Anatomy, Metatarsal Bones - Gross Anatomy Foot Bone Anatomy Author: Vinod K Panchbhavi, MD, FACS; Chief Editor: Thomas R Gest, PhD more... Share Overview Overview The human foot is a highly developed, biomechanically complex structure that serves to bear the weight of the body as well as forces many times the weight of the human body during propulsion. About 26 bones in the human foot provide structural support. They can be grouped into 3 parts, as follows [ 1 , 2 ] : The tarsal bones (7) [ 3 , 4 ] The metatarsal bones (5) [ 5 ] The phalanges (14) [ 6 ] Apart from these main bones, the sesamoid bones help improve function and are often found as variants of the accessory bones. The foot itself can be divided into 3 parts: the hindfoot, the midfoot, and the forefoot.

The hindfoot is composed of 2 of the 7 tarsal bones, the talus, and the calcaneus; the midfoot contains the rest of the tarsal bones; and the forefoot contains the metatarsals and the phalanges. The images below depict the bones of the foot. Bones of the foot, dorsal and ventral views. Next: Tarsal Bones - Gross Anatomy The tarsal bones are 7 in number. They are named the calcaneus, talus, cuboid, navicular, and the medial, middle, and lateral cuneiforms. Calcaneus The calcaneus is the largest of the tarsal bones located in the heel of the foot and bears the weight of the body as the heel hits the ground. This bone protrudes out at the back, providing a strong lever for the triceps surae muscles of the calf and helping with plantar flexion and push off during ambulation (see the image below). The calcaneus is roughly 3-dimensionally rectangular in shape, with its long axis directed anteriorly and laterally, and it has 6 surfaces. Ankle joint, lateral view.

View Media Gallery Calcaneus, surface anatomy The superior calcaneal surface (see the following images) of the calcaneus has 2 parts: articular and nonarticular. The nonarticular part extends posteriorly to form the heel; it varies in length in different individuals, is convex from side to side, is concave in the anteroposterior axis, and supports a fat pad situated anterior to the calcaneal (Achilles) tendon. The articular part that lies anterior to the nonarticular part of the superior surface has an oval facet; the posterior facet faces superiorly and is also tilted anteriorly. The articular portion of the superior surface is convex in the anteroposterior axis and articulates with the posterior calcaneal facet on the undersurface of the talus. Superior surface of the calcaneus bone. View Media Gallery At the anterior boundary of the posterior facet is a deep depression, which continues posteromedially in the form of a groove. This groove is called the calcaneal sulcus. It matches the inferior similar sulcus underneath the talus, and both these grooves form a canal in the hindfoot called the sinus tarsi.

Just anteromedial to the calcaneal sulcus is another area of articular surface elongated and concave in its long axis that is directed anterolaterally. This articular surface is divided by a transversely oriented notch into a larger facet, called the middle facet, as well as a smaller facet anterior to this, called the anterior facet (see the previous image). The middle facet lies on a medially projecting process of the calcaneus called the sustentaculum tali (see the image below). It articulates with the middle calcaneal facet on the under surface of the talus. The anterior facet lies on the anterior process of the calcaneus and articulates with the anterior calcaneal facet on the talus. The upper surface, anterior and lateral to the facets, is rough for the attachment of ligaments and for the origin of the extensor digitorum brevis. Medial surface of the calcaneus bone. View Media Gallery The inferior or plantar calcaneal surface is wider posteriorly and convex from side to side.

It has a plantar prominence at the back, called the calcaneal tuberosity (see the following image), which has a central longitudinal depression dividing it into a smaller lateral process that is the origin of a part of the abductor digiti minimi (quinti), as well as a larger broader medial process that gives attachment, by its prominent medial margin, to the abductor hallucis, and in front to the flexor digitorum brevis and the plantar aponeurosis. Lateral view of the calcaneus and cuboid bones. View Media Gallery The depression between the processes gives rise to the abductor digiti minimi (quinti). The rough surface in front of the processes gives attachment to the long plantar ligament and to the lateral head of the quadratus plantae. The plantar calcaneocuboid ligament is attached to a prominent tubercle nearer the anterior part of this surface, as well as to a transverse groove in front of the tubercle. The lateral calcaneal surface (see the image below) is broader posteriorly and becomes narrower anteriorly. It has a small tubercle in the middle, to which the calcaneofibular ligament is attached.

Anterior to this tubercle are 2 grooves separated by a ridge, the trochlear process or peroneal (fibular) tubercle. The fibularis (peroneus) brevis tendon lies superior and the fibularis (peroneus) longus tendon lies inferior to the peroneal (fibular) tubercle. Lateral surface of the calcaneus bone. View Media Gallery The medial calcaneal surface (see the first image below) has a deep concavity in the anteroposterior direction in which run the neurovascular structures from the leg into the foot. Toward the upper and anterior end is a medially oriented horizontal projection, the sustentaculum tali (see the second image below). The sustentaculum tali has an articular surface for the middle calcaneal facet and is grooved inferiorly to house the flexor hallucis longus tendon. Its anterior margin gives attachment to the plantar calcaneonavicular ligament, and its medial margin gives attachment to a part of the deltoid ligament of the ankle joint. Medial surface of the calcaneus bone.

View Media Gallery Talus The talus is the second largest tarsal bone, and it is situated above the calcaneus in the hindfoot. This bone is unique in that two thirds of the talar surface is covered with articular cartilage, and neither tendons nor muscles insert or originate from this bone. The talus has 5 articular surfaces, all of which have a weight-bearing function. The talus is composed of 3 parts (the head, neck, body) and 2 processes (the lateral and posterior). The talar head is the portion that articulates mostly with the navicular. The body includes the dome of the talus at the ankle joint and the posterior facet at the subtalar joint. Between the head and the body is the neck, which does not articulate with the ankle and sits over the sinus tarsi below. The body and neck of the talus are not coaxial, because in the horizontal plane the neck angles medially with a variable angle of declination. Talus, head The talar head looks forward and medialward; its anterior articular or navicular surface is large, oval, and convex.

The anteroinferior medial portion of the talar head is quadrilateral or oval and provides articulation with the anterior facet of the calcaneus. This portion of the head is flat and continuous anteriorly with the navicular articular surface (see the images below). Anterior view of the talus and calcaneus bones. View Media Gallery The head of the talus nests within an articulation known as the acetabulum pedis, or foot socket (see image below), as described by Sarrafian. [ 2 ] This socket is formed by the calcaneal middle and anterior surfaces connected to the large navicular articular surface by the inferior and superomedial calcaneonavicular ligaments. The acetabulum pedis has a variable volume capacity and adapts to the changing position of the talar head during gait. It is hinged laterally by the lateral calcaneonavicular component of the bifurcate ligament and medially by the posterior tibial tendon and the spring ligament. Superior view of the acetabulum pedis.

View Media Gallery Talus, neck The neck is directed forward and medialward 15-20º and comprises the constricted portion of the bone between the body and the oval head (see the following image). This portion of the talus is most vulnerable to fracture. The neck has 4 surfaces: (1) superior, (2) lateral, (3) medial, and (4) inferior. Medial surface of the talus bone. View Media Gallery The superior surface of the neck is limited posteriorly by the anterior border of the trochlea of the talus (the dome or body) and anteriorly by the articular surface of the talar head. The tibiotalar capsule inserts along this superior surface just proximal to the insertion of the capsule of the talonavicular joint. The lateral surface of the neck is concave and is continuous below with the deep groove for the interosseous talocalcaneal ligament. It provides an insertion for the medial aspect of the inferior extensor retinaculum. The inferior surface of the neck forms the roof of the sinus tarsi and sinus canal. The medial surface provides an area for insertion of the talonavicular ligaments.

Talus, body The body of the talus is arbitrarily divided into 5 surfaces: (1) lateral, (2) medial, (3) superior, (4) inferior, and (5) posterior. The lateral talar body surface carries a large triangular facet, concave from above downward, for articulation with the lateral malleolus (see the image below). It is continuous above with the superior articular surface and in front of it is a rough depression for the attachment of the anterior talofibular ligament. Along the anterior, inferior, and posterior perimeter of this lateral articular surface is the lateral process, a nonarticular component of the talus. The lateral talocalcaneal ligament inserts at the inferior tip of the lateral process. Along the anterior border of the triangular lateral process are 2 tubercles for insertion of the anterior talofibular ligament. Along the posteroinferior border of this lateral surface lies a groove for the attachment of the posterior talofibular ligament. Lateral surface of the talus bone. View Media Gallery The medial talar body surface of the body presents 2 areas, superior and inferior(see the following image).

The superior portion is occupied by a pear-shaped or comma-shaped articular facet, which is broader anteriorly and is called the medial malleolar facet. It articulates with the medial malleolus of the tibia and is continuous above with the superior articular surface for tibia. The long-axis medial malleolar facet is oriented anteroposteriorly. The inferior portion is nonarticular, and its anterior half is a depressed surface perforated by numerous vascular foramina. Under the tail of the medial malleolar facet, the posterior half of the inferior portion consists of a large oval area that provides insertion for the deep component of the deltoid ligament. Medial surface of the talus bone. View Media Gallery The superior surface of the talar body is completely covered with articular cartilage for articulation with the tibia. It is shaped like a pulley, with the groove of the pulley termed the trochlea, closer to the medial border. The superior surface is broader in front than behind, convex anteroposterior axis, slightly concave from side to side: in front, it is continuous with the upper surface of the neck of the bone (see image below). Superior surface of the talus bone.

View Media Gallery The inferior talar body surface presents 2 articular areas called the posterior calcaneal articular surface and the middle calcaneal articular surface . These articular surfaces, one for the posterior and the other for the middle calcaneal facets, are separated from each other by a deep groove, the sulcus tali. The groove runs obliquely forward and lateralward, becoming gradually broader and deeper in front. In the articulated hindfoot it lies above a similar groove upon the upper surface of the calcaneus, and forms, with it, a canal termed the sinus tarsi, in which lies the interosseous talocalcaneal ligament. The posterior calcaneal articular surface is large and of an oval or oblong form. It articulates with the corresponding facet on the upper surface of the calcaneus and is deeply concave in the direction of its long axis, which runs forward and lateralward at an angle of about 45° with the median plane of the body. The middle calcaneal articular surface is small, oval in form and slightly convex; it articulates with the upper surface of the sustentaculum tali of the calcaneus(see the first image below).

The posterior surface is narrow, and traversed by a groove running obliquely downward and medialward and transmitting the tendon of the flexor hallucis longus (see the second image below). Medial view of the talus and calcaneal bones. View Media Gallery The sulcus for this tendon is flanked by the posterolateral and posteromedial tubercles. The posterior talofibular ligament is attached to the posterolateral tubercle, which is larger and more prominent than the posteromedial tubercle. The posterolateral tubercle contributes an inferior articular surface that is in continuity with the posterolateral aspect of the posterior calcaneal surface of the talus. An accessory bone, the os trigonum, may be found in connection with the posterolateral tubercle. Talus, articulations The talus articulates with 4 bones: the tibia, fibula, calcaneus, and navicular. Cuboid The cuboid bone is placed on the lateral side of the foot, in front of the calcaneus, and behind the fourth and fifth metatarsal bones. It is cuboidal in shape but has a broader base oriented medially (see the image below).

Lateral view of the calcaneus and cuboid bones. View Media Gallery Cuboid, surfaces The dorsal cuboidal surface, directed upward and lateralward, is rough, for the attachment of ligaments. The plantar surface appears in front of a deep groove, the peroneal (fibularis) sulcus, which runs obliquely anteromedially. It lodges the tendon of the fibularis (peroneus) longus and is bounded behind by a prominent ridge, to which the long plantar ligament is attached. The ridge ends laterally in an eminence, the tuberosity, the surface of which presents an oval facet; on this facet glides the sesamoid bone or cartilage frequently found in the tendon of the fibularis (peroneus) longus. The surface of bone behind the groove is rough, for the attachment of the plantar calcaneocuboid ligament, a few fibers of the flexor hallucis brevis, and a fasciculus from the tendon of the tibialis posterior. The lateral cuboidal surface presents a deep notch formed by the commencement of the peroneal (fibularis) sulcus.

The posterior surface is smooth, triangular, and concavoconvex, for articulation with the anterior surface of the calcaneus; its inferomedial angle projects backward as a process, which underlies and supports the anterior end of the calcaneus. The anterior cuboidal surface, of smaller size, but also irregularly triangular, is divided by a vertical ridge into 2 facets: the medial, quadrilateral in form, articulates with the fourth metatarsal; the lateral, larger and more triangular, articulates with the fifth metatarsal. The medial surface is broad, irregularly quadrilateral, and presents at its middle and upper part a smooth, oval facet, for articulation with the third cuneiform; and behind this (occasionally), a smaller facet, for articulation with the navicular; it is rough in the rest of its extent, for the attachment of strong interosseous ligaments. Cuboid, articulations The cuboid articulates with 4 bones: (1) calcaneus, (2) third cuneiform, (3) fourth metatarsal, and (4) fifth metatarsal. It occasionally articulates with a fifth, the navicular.

Navicular bone The navicular bone is located medially in the midfoot between the talus posteriorly and the 3 cuneiform bones anteriorly (see the following image). It forms the uppermost portion of the medial longitudinal arch of the foot and acts as a keystone of the arch. It is a boat-shaped bone that sits between the talar head and the 3 cuneiform bones. The navicular bone has 6 surfaces. Bones of the foot, larger lateral view. View Media Gallery Navicular bone, surfaces The posterior navicular surface is oval, concave, broader laterally than medially, and articulates with the rounded head of the talus (see the image below). Posterior surface of the navicular bone. View Media Gallery The medial navicular surface slopes posteriorly to end in a rounded prominent tuberosity (see the image below), where a portion of the posterior tibial tendon is inserted. Much of the tuberosity accepts the attachment of the plantar calcaneonavicular (spring) ligament arising from the sustentaculum tali. Superior view of the talus and navicular bones.

View Media Gallery The anterior navicular surface is convex from side to side, and subdivided by 2 ridges into 3 facets, for articulation with the 3 cuneiform bones. The dorsal surface is convex from side to side, and rough for the attachment of ligaments (see the following image). The plantar surface is irregular, and also rough for the attachment of ligaments. The lateral surface is rough and irregular for the attachment of ligaments and occasionally presents a small facet for articulation with the cuboid bone. Dorsal surface of the navicular bone. View Media Gallery Navicular bone, articulations The navicular articulates with 4 bones: the talus and the 3 cuneiforms. It occasionally articulates with a fifth, the cuboid. Cuneiforms The 3 cuneiforms are named the medial, middle, and lateral, and they are convexly shaped on their broader dorsal surfaces. The middle and the lateral cuneiforms are also wedge shaped, so that the apex of each bone points plantarward and toward the center of the foot. The medial cuneiform is convex medially and rounded inferiorly.

The medial and lateral cuneiforms project farther distally that the middle cuneiform to create a mortise for the base of the second metatarsal that articulates with the middle cuneiform. This configuration creates a keystone effect and contributes to the stability of the midfoot. See the following images. Bones of the foot, dorsal and ventral views. View Media Gallery Medial cuneiform overview, surfaces, and articulations The medial cuneiform bone is the largest of the 3 cuneiforms. It is situated at the medial side of the foot, between the navicular behind and the base of the first metatarsal in front. The medial surface of the medial cuneiform is subcutaneous, broad, and quadrilateral. At its anterior inferior edge is a smooth oval impression, into which part of the tendon of the tibialis anterior is inserted; in the rest of its extent, it is rough for the attachment of ligaments.

The lateral surface is concave, presenting, along its superior and posterior borders a narrow L-shaped surface, the vertical limb and posterior part of the horizontal limb which articulate with the second cuneiform, whereas the anterior part of the horizontal limb articulates with the second metatarsal bone. The rest of this surface is rough for the attachment of ligaments and part of the tendon of the fibularis (peroneus) longus. The anterior surface, kidney shaped and much larger than the posterior surface, articulates with the first metatarsal bone. The posterior surface is triangular, concave, and articulates with the most medial and largest of the 3 facets on the anterior surface of the navicular. The plantar surface is rough and forms the base of the wedge; at its back part is a tuberosity for the insertion of part of the tendon of the tibialis posterior. It also gives insertion in front to part of the tendon of the tibialis anterior. The dorsal surface is the narrow end of the wedge and is directed upward and lateralward; it is rough for the attachment of ligaments.

The first cuneiform articulates with 4 bones: (1) navicular, (2) second cuneiform, (3) first metatarsal, and (4) second metatarsal. Middle cuneiform overview, surfaces, and articulations The second cuneiform bone, the smallest of the 3, is wedge shaped with a dorsal base and apex plantar. It is situated between the other 2 cuneiforms, and articulates with the navicular behind and the second metatarsal in front. The anterior surface of the middle cuneiform bone, triangular in form, and narrower than the posterior, articulates with the base of the second metatarsal bone. The posterior surface, also triangular, articulates with the intermediate facet on the anterior surface of the navicular. The medial surface carries an L-shaped articular facet, running along the superior and posterior borders, for articulation with the first cuneiform, and is rough in the rest of its extent for the attachment of ligaments. The lateral surface presents posteriorly a smooth facet for articulation with the third cuneiform bone. The dorsal surface forms the base of the wedge; it is quadrilateral and rough for the attachment of ligaments.

The plantar surface, sharp and tuberculated, is also rough for the attachment of ligaments and for the insertion of a slip from the tendon of the tibialis posterior. The medial cuneiform articulates with 4 bones: (1) navicular, (2) first cuneiform, (3) third cuneiform, and (4) second metatarsal. Lateral cuneiform overview, surfaces, and articulations The anterior surface of the lateral cuneiform is triangular and articulates with the third metatarsal bone. The posterior surface articulates with the lateral facet on the anterior surface of the navicular and is rough below for the attachment of ligamentous fibers. The medial surface of the lateral cuneiform presents an anterior and a posterior articular facet, separated by a rough depression: the anterior, sometimes divided, articulates with the lateral side of the base of the second metatarsal bone; the posterior skirts the posterior border and articulates with the second cuneiform; the rough depression gives attachment to an interosseous ligament.

The lateral surface of the lateral cuneiform also presents 2 articular facets, separated by a rough nonarticular area; the anterior facet, situated at the superior angle of the bone, is small and semi-oval in shape, and articulates with the medial side of the base of the fourth metatarsal bone; the posterior and larger one is triangular or oval and articulates with the cuboid; the rough, nonarticular area serves for the attachment of an interosseous ligament. The 3 facets for articulation with the 3 metatarsal bones are continuous with one another; those facets for articulation with the second cuneiform and navicular are also continuous, but the facet for articulation with the cuboid is usually separate. The dorsal surface is oblong, its posterolateral angle being prolonged backward; whereas the plantar surface is a rounded margin and serves for the attachment of part of the tendon of the tibialis posterior, part of the flexor hallucis brevis, and ligaments.

The third cuneiform articulates with 6 bones: (1) navicular, (2) second cuneiform, (3) cuboid, and (4-6) second, third, and fourth metatarsals. Previous View Media Gallery The base at the proximal end is wedge-shaped, articulating proximally with the tarsal bones and by its sides with the contiguous metatarsal bones; its dorsal and plantar surfaces are rough for the attachment of ligaments. The head at the distal end presents a convex articular surface, oblong from above downward, and extending farther backward plantar than dorsal. Its sides are flattened, and on each is a depression, surmounted by a tubercle, for ligamentous attachment. Its plantar surface is grooved anteroposteriorly (for the passage of the flexor tendons) and marked on either side by an articular eminence continuous with the terminal articular surface. First metatarsal bone The first metatarsal bone is the stoutest and the shortest of the metatarsal bones. The body is strong and of well-marked prismoid form.

The base usually has no articular facets on its sides, but occasionally on the lateral side an oval facet exists, by which it articulates with the second metatarsal. Its proximal articular surface is of large size and kidney shaped; its circumference is grooved (for the tarsometatarsal ligaments) and medially gives insertion to part of the tendon of the tibialis anterior; its plantar angle presents a rough, oval prominence for the insertion of the tendon of the fibularis (peroneus) longus. The head is large; on its plantar surface are 2 grooved facets, on which glide sesamoid bones; the facets are separated by a smooth elevation. Second metatarsal bone The second metatarsal bone is the longest of the metatarsal bones, as it extends proximally the most, articulating with the recessed middle cuneiform. Its base is broad above, narrow and rough below.

It presents 4 articular surfaces: one behind, of a triangular form, for articulation with the second cuneiform; one at the upper part of its medial surface, for articulation with the first cuneiform; and 2 on its lateral surface, an upper and lower, separated by a rough nonarticular interval. Each of these lateral articular surfaces is divided into 2 by a vertical ridge; the 2 anterior facets articulate with the third metatarsal; the 2 posterior (sometimes continuous) with the third cuneiform. A fifth facet is occasionally present for articulation with the first metatarsal; it is oval in shape and situated on the medial side of the body near the base. Third metatarsal bone The third metatarsal bone articulates proximally, by means of a triangular smooth surface, with the third cuneiform; medially, by 2 facets, with the second metatarsal; and laterally, by a single facet, with the fourth metatarsal. This last facet is situated at the dorsal angle of the base.

Fourth metatarsal bone The fourth metatarsal bone is smaller than the preceding metatarsal bones; its base presents an oblique quadrilateral surface for articulation with the cuboid; a smooth facet on the medial side, divided by a ridge into an anterior portion for articulation with the third metatarsal, and a posterior portion for articulation with the third cuneiform. On the lateral side, a single facet, for articulation with the fifth metatarsal, can be found. Fifth metatarsal bone The fifth metatarsal bone is recognized by a rough eminence, the tuberosity, on the lateral side of its base. The base articulates behind, by a triangular surface cut obliquely in a transverse direction, with the cuboid, and medially, with the fourth metatarsal. The tendon of the fibularis (peroneus) tertius inserts on the medial part of its dorsal surface. The fibularis (peroneus) brevis inserts on the dorsal surface of the tuberosity. A strong band of the plantar aponeurosis connects the projecting part of the tuberosity with the lateral process of the tuberosity of the calcaneus.

The plantar surface of the base is grooved for the tendon of the abductor digiti (minimi) quinti and gives origin to the flexor digiti minimi (quinti) brevis. Metatarsal articulations The base of each metatarsal bone articulates with one or more of the tarsal bones, and the head articulates with one of the first row of phalanges. The first metatarsal articulates with the first cuneiform, the second with all 3 cuneiforms, the third with the third cuneiform, the fourth with the third cuneiform and the cuboid, and the fifth with the cuboid. Previous View Media Gallery Proximal phalanges The body of each proximal phalanx is similar to the metatarsals in being convex above and concave below. The base is concave for articulation with the respective metatarsal, and the head presents a trochlear surface for articulation with the second phalanx. Middle phalanges The middle phalanges are smaller than the proximal ones but larger than the distal phalanges; the features at the base and head are similar to the proximal phalanges.

Distal phalanges The distal phalanges are flattened from above downward; each presents a broad base for articulation with the corresponding bone of the second row and an expanded distal tip for the support of the nail and end of the toe. Sesamoids of the foot Galen apparently first coined the term sesamoid because of the resemblance of these small rounded bones to the sesame seed. [ 7 ] The location of the sesamoids in the foot is constant, but the frequency of occurrence may vary. [ 8 ] The sesamoids give a mechanical advantage to the musculotendinous unit in which they are located and reduce friction and pressure in the nearby joint. The sesamoids may be totally or partially contained within the tendinous structure, and they may ossify or remain cartilaginous or partially ossify with a fibrocartilaginous interface between the ossified fragments. This variability in ossification might explain the radiographic absence or presence of various sesamoid bones, as well as the incidence of bipartism of sesamoids. Previous Superior view of the acetabulum pedis. Medial view of the talus and calcaneal bones.

Lateral view of talus and calcaneal bones. Anterior view of the talus and calcaneus bones. Lateral view of the calcaneus and cuboid bones. Anterior surface of the calcaneus bone. Lateral surface of the calcaneus bone. Medial surface of the calcaneus bone. Superior surface of the calcaneus bone. Superior surface of the talus bone. Medial surface of the talus bone. Lateral surface of the talus bone. Posterior surface of the talus bone. Inferior surface of the talus bone. Superior view of the talus and navicular bones. Posterior surface of the navicular bone. Dorsal surface of the navicular bone. of 23

Question: The Calcaneusis the medical name for which bone in the human body?
Answer: HEEL BONE